Haemonetics SEBRA 1040, Service Manual

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Product Description 2-3
P/N 108755-US, Manual revision: AA
T
HEORY OF
O
PERATION
The Shaker is a microprocessor-controlled instrument. All the functions needed
to collect blood, such as mixing, stopping the flow, displaying and indicating the
flow, etc., are managed by programs that are permanently written into the micro-
chips ("firmware"). Parameter settings for a particular collection, such as bag type,
collection volume, etc., are stored in the Shaker's memory and are used by the
firmware when the collection is performed.
Note: If the parameters are not changed, the firmware will always use the last pa-
rameters entered.
The blood bag rests upon the Shaker bag tray portion of the shroud assembly in
an orientation that allows a gentle end-to-end agitation of the blood. The bag tilts
over an approximate angle of 32° at an oscillation of approximately 38 cycles per
minute.
The collection process is monitored continuously to ensure the required weight
or volume is obtained. The blood weight is compared to the desired collection
weight. If the weight is equal to the desired collection weight, the Shaker clamps
the bag tubing (which stops the blood flow), illuminates a continuous red
indicator light, and sounds an audible alert. The Shaker continues to agitate the
blood until the operator terminates the process.
The Shaker also uses the weight measurement for another task. As the blood is
collected, the Shaker measures the weight once every mixing cycle. The Shaker
compares the weight at one cycle to that of the previous cycle, and the rate of
collection is automatically calculated. The rate of collection is compared to inter-
nally stored parameters; and if it falls below the minimum rate, a red indicator
light flashes to tell the operator that an inadequate or no flow condition exists.